Refrigerating apparatus



July 14, 1931 J. w. CARL REFRIGERATING APPARATUS Filed May 30, 1928 vrrlu Patented July 14, 1931 UNITED STATES PATENT OFFICE um W. CARL, OF DAYTON, OHIO, ASSIGNOR TO FBIGIDAIRE CORPORATION, 01'

DAYTON, OHIO, A CORPORATION OF REFRIGERATING "APPARATUS Application filed May 30,

This invention relates to refrigerating apparatus and particularly to a refrigerating device for motor vehicles.

One of the objects of the invention is to provide an improved refrigerating element which can be dis osed within a small height and which afior s a relatively large amount of effective refrigerating surface.

Another object of the invention is to provide an improved form of refrigerating element which will promote the effective and uniform circulation of air throughout a refrigerator compartment.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawin s wherein a preferred form of the present invention is clear ly shown.

In the drawings:

Fig. 1 is a longitudinal vertical section of a portion of a motor vehicle provided with a refrigerating system constructed in accordance with the present invention, I

Fig. 2 is a side elevation of a refrigerating element, and

Fig. 3 is a front elevationof the element.

In refrigerated motor vehicles such as ice cream trucks the matter of head room or available height for the storage of goods in the refrigerated compartment is very important. Since the bodies of vehicles of this character are very heavy they must be kept low in order not to raise the center of gravity of the vehicle. For this reason it becomes important to provide a refrigerating element having a relatively large amount of surface, snfiicient to cool a large-sized compartment, but which can be disposed within a very small height. The invention is concerne among other things, with providing an improved evaporator particularly adapted for this class of service.

Referring to the drawings, 10 designates an insulated compartment which may be car- 1928. Serial No. 281,610.

ried by a motor vehicle having a machine compartment 12 containing refrigerating apparatus generally denoted by 13 and a power plant generally denoted by 14. The refrigerating apparatus includes a compressor 15 driven by a motor 16 for supplying refrigerant through a liquid refrigerant line 17 to the refrigerating elements generally denoted by 18, from which gaseous or evaporated refrigerant is returned to the compressor through the vapor line 19.

In the present embodiment two refrigerating elements 18 are connected in arallel cir cuit relation. Each element inclu es a header or tank 20 which providesa reservoir for liquid refrigerant supplied to the header through the liquid inlet 21 under the control of a float valve 22 which maintains a constant liquid level 23. Radiating from the header are a number of refrigerant ducts or conduits which communicate with the header at one end and are closed at the other end. The conduits are arranged in oups, each group including two sets of con uits, one set 24 being shown in full lines in Fig. 3 and the other set 2411 being indicated in dotted lines in the same figure. The conduits in each set are arranged in a plane and the two sets of each group are slightl displaced from each other axially along t e header. The conduits in one set are disposed between the conduits in the other set around the header. A fin 25 is placed between the two sets of conduits in each group and is soldered to all of the conduits of that group. For this purpose the conduits are preferably flattened to provide a large surface which can be readilv attached to the fins while the open end 0 each is round to facilitate attachment to the header. The fins are relatively wide and relatively short in the vertical direction and are disposed partially around the header in order to provide a relatively large refrigerating surface within a relatively small vertical height.

Where refrigerant conduits are soldered to fins in this manner it has been found that there is a limited area along the conduit throughout which the fin will transmit heat to the conduit at a sufficiently rapid rate to be effective as a practical refrigerating surface. This area depends upon the temperature difference between the refrigerant in the conduit and the atmosphere to be refrigerated, and the thickness of the fin, but for a given set of conditions there is a fairly definite and determinable distance from the conduit beyond which the fin is ineffective, practically speaking, as a refrigerating surface. That is, while surfaces at a greater distance than this will of course absorb some heat and the fin will transfer some of this heat .to the conduit, the resistance to such heat flow is so great that the amount of heat which reaches the refrigerant is negligible for practical refrigerating purposes. The distance from the refrigerant conduit thru which the fin is a practical refrigerating surface, I call the refrigerating range of the conduit. As a rough indication of this range in ordinary ice-cream truck practice under normal conditions, for example, it may be said that when refrigerant is being evaporated in the conduit the portion of the fin within the refrigerating range will become coated with frost. However this is not necessarily an exact indication, since the area of frosting will depend on such varying conditions as the humidity of the atmosphere. It will thus be seen that the factor which limits the refrigcrating power of a fin of this sort in given circumstances is the distance from any given portion of the fin to the refrigerating a cut and not the amount of refrigeration which can be supplied at some concentrated point such as the refrigerant conduit. The maximum permissible distance has been determined by experiment by attaching a conduit to a plate or fin in the manner indicated andg.

evaporating the refrigerant in the conduit under normal conditions.

A feature of the present invention is the distribution of ducts 24 and 24a throughout the fin at an interval which is less than twice the normal frosting range of the conduits and so that all points of the fin are within the refrigerating range. By keeping the conduits flooded with evaporating liquld refrigerant, the temperature along the conduit is uniform, and by connecting the conduits in arallel the temperature of each conduit is t e same. By this means the entire surface of the fin is an effective refrigerating surface of substantially the same temperature.

The refrigerating elements 18 are sus pended from the top wall of the compartment by any suitable means such as hangers 30 and are disposed as close to the top wall as frosting conditions and the requirements of air circulation will permit.

In practice the space 31 between the top wall and the top of the header is just suificient to allow the building up of the usual coating of frost during operation without touching the top wall. In other words, the refrigerating element including its coating of frost will be just out of contact with the top wall. It will be noted that the conduits all slope from the header and communicate therewith below the level of the liquid so that liquid refrigerant can always flow by gravity to all points of the conduits and evaporated refrigerant can readily flow back to the header. The top edges 32 of the fins are inclined to conform to the inclination of the outermost conduits 34 and are at the limit of the refrigerating range of these conduits. Likewise the outermost conduits are placed at the minimum inclination from the horizontal which permits effective circulation of the refrigerant. In this manner, as will be seen from Figs. 1 and 3, a. sufficient space is provided between the top wall of the compartment 10 and the top edges of the fins 25 to permit the rapid circulation of air over the fins, while the refrigerating element as a whole occupies a. relatively small amount of head room.

W'hile the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

I claim:

1'. A refrigerating element for refrigerating apparatus comprisin a header forming a reservoir for liquid re rigerant, transverse fins extending laterally beyond the header and a plurality of sets of conduits connected to the header in parallel circuit relation, the conduits being radiall arranged with respect to the header, both sides of each fin being in intimate thermal association with a set of conduits.

2. A refrigerating element for refrigeratmg apparatus comprising a header forming a reservoir for liquid refrigerant, transverse fins extending laterally beyond the header and a plurality of sets of conduits connected to the header in parallel circuit relation, the conduits being radially arranged with respect to the header and each fin being in intimate thermal association with a plurality of sets of conduits.

3. A refrigerating element for refrigerating apparatus comprising a header forming a reservoir for liquid refrigerant, transverse fins partially surrounding the header and extending laterally beyond the header, and a. plurality of conduits for circulating refrigerant connected to the header in parallel circuit relation and radially arranged with respect to the header, each fin being in intimate thermal association with a. plurality of said conduits.

4. A refrigerating element for refrigerat Ni W ing apparatus comprising a header forming a reservoir for l1qu1d refrigerant, transverse fins partially surrounding the header and extending laterally beyond the header, and a plurality of conduits for circulating refrigerant connected to the header in parallel circuit relation and radially arranged with respect to the header, each fin being in intimate thermal association with a plurality of said conduits.

In testimony whereof I hereto aifix my signature.

JAMES W. CARL.

ing apparatus comprising a header forming a reservoir for liquid refrigerant, transverse fins partially surrounding the header and extending laterally beyond the header, and a plurality of conduits for circulating refrigerant connected to the header in parallel circuit relation and radially arranged with respect to the header, each fin being in intimate thermal association with a plurality of said 10 conduits.

In testimony whereof I hereto affix my signature.

JAMES W. CARL.

CERTIFICATE OF CORRECTION.

Patent No. 1,813,987. Granted July 14. 1931. to

JAMES W. CARL.

it is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, line 122, claim 3, strike out the words "partially surrounding the header and; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 18th day of August, A. D. 1931.

M. J. Moore, (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent No. 1.813.987. Granted July 14. 1931. to

JAMES W. CARL.

[t is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, line 122, claim 3, strike out the words "partially surrounding the header and; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 18th day of August, A. D. I931.

M. J. Moore, (Seal) Acting Commissioner of Patents. 

